Not sure if this was a question or just a comment, but...
In firefox, type about:config in the URL box, then in the filter box (Alt+I) type "checkDefaultBrowser". Select the "browser.shell.checkDefaultBrowser" option and change it to "true". Restart, and answer "Yes" to make default.
Another option: start firefox from the command line (if running Windows, Start->Run->cmd or some such), with the following command: "firefox -silent -setDefaultBrowser"
HTH